James Barton Longacre
75% Copper, 25% Nickel
The 1868 Three-Cent Nickel is a very common coin, with hundreds of certified Mint State example available to collectors. Gems are relatively common, even up to MS66. However, anything better is extremely rare -- the finest is a single PCGS MS67.
The overall strike quality for this date is slightly better than the 1867, but most examples still show incomplete lines in the "I"s on the reverse.